A variety of medical devices are commonly used to access remote regions of the body to deliver diagnostic or therapeutic agents and to perform surgical procedures on those regions. For example, flexible endoscopes can use various body passageways (such as the alimentary and excretory canals and airways) to access the colon, esophagus, stomach, urethra, bladder, ureter, kidney, lungs, bronchi, uterus, and other organs. Catheters may use the circulatory system as pathways to access treatment sites near the heart.
These medical devices are often introduced into the body through a large artery such as those found in the groin or in the neck, through the anus to access the colon and intestinal tract, or through the urethra to access the urinary system. The devices are often passed through ever-narrower arteries and canals until they can reach the operative site inside the body. Many such pathways may curve, loop around, and even wind back. In order to navigate the medical device through the pathways to the operative site, the medical device must be flexible to allowing bending, yet have enough column strength to prevent buckling of the medical device as it is pushed.
Some endoscopes and electrophysiology catheters can steer or deflect the distal tip of the endoscope to follow the pathway of the anatomy under examination such as the colon, bladder, kidney, and heart. Deflection or articulation is often a desirable characteristic in these types of medical devices to minimize friction force and trauma to the surrounding tissue, and to survey targeted examination sites. Navigation of the endoscope through various areas within a patient improves the success of the examination and minimizes pain, side effects, risk, or sedation to the patient.
In some known devices, to achieve active deflection at the distal flexible portion of the device, the endoscope may use a force created on one end of the device, usually at a handle. The force is then transmitted to the articulation section by control cables or pull-wires. The pull-wires are carried within the endoscope shaft connecting the distal end to a set of controls in the handle. By manipulating the controls, the operator is able to steer the distal end portion of the endoscope during insertion and direct it to a region of interest within the body of the patient.
In some situations, it may be desirable to provide one or more rigid portions of the endoscope along its length. For example, it may be desirable to modify the flexibility of (e.g., strengthen or make more rigid) a selected portion of the endoscope such as, for example, just proximal to a deflectable distal end portion. Such a feature may provide better control and maneuverability of the endoscope within the body of a patient.
In some situations, it may be desirable to provide deflection or articulation of more than just the deflectable distal end portion of an endoscope. For example, it may be desirable to add a secondary or passive deflection portion proximal of the active deflection portion (e.g., distal end portion).